Klotho regulation and aging

描述(申请人提供)：我们研究的重点是研究年龄抑制蛋白Klotho是如何随着大脑的衰老而调节的。当Klotho的表达被消除时，小鼠发育正常，但在4个月大时就会变老致死。这种快速恶化伴随着一种与老年人相似的表型(认知障碍、动脉粥样硬化、异位钙化、肺气肿、骨质疏松症、皮肤萎缩和脱发、胸腺退化、不孕不育和骨密度下降)。Klotho在小鼠体内的消除会导致认知障碍，这与氧化应激增加有关。相比之下，Klotho过度表达的转基因小鼠的寿命最高可延长30%，并能抵抗氧化应激。我们的团队发现Klotho在老化的非人类灵长类动物、大鼠和小鼠的大脑中一起下调，这导致我们假设Klotho在大脑功能中很重要，随着年龄的增长，Klotho的下调可能是氧化应激的结果，如果加以预防，可能会改善退化为神经退行性疾病的情况。这项工作旨在研究Klotho启动子和3‘非编码区随年龄的调节，以及氧化损伤对Klotho启动子随年龄的影响。我们将确定Klotho启动子的高GC含量是否使其成为年龄相关下调的目标，因为氧化应激会随着时间的推移而积累损伤。这将通过将Klotho启动子的氧化状态与其他基因的氧化状态进行比较，无论是在体外还是在老年恒河猴大脑的死后样本中。我们还将致力于鉴定结合和诱导Klotho启动子激活的转录因子。Klotho启动子不包含转录启动的经典元件。了解Klotho转录的重要因素可能有助于了解导致Klotho激活的信号通路以及Klotho在正常细胞中的作用。最后，我们将确定Klotho是否受microRNAs(MiR)的调节，以及miR如何随年龄变化。MiR结合并调控mRNA的翻译，目前尚不清楚miR是否以及如何影响Klotho加工。同样，了解调节Klotho的过程将使我们更好地了解影响Klotho和Klotho在细胞功能中更广泛作用的过程。这项工作的结果将增加关于抗衰老基因Klotho的新知识，并阐明氧化损伤如何选择性下调特定基因的可能机制。 公共卫生相关性：随着人口的迅速老龄化，与年龄相关的疾病的增加预计将在未来50年上升到前所未有的水平。了解已知的影响衰老过程并受其影响的基因的调节，对于开发一系列疾病的新疗法至关重要。衰老抑制蛋白Klotho在大脑中随着年龄的增长而减少，可能是治疗神经退行性疾病的靶点。

DESCRIPTION (provided by applicant): The focus of our study is to examine how the age suppressor protein, Klotho, is regulated with aging in the brain. When Klotho expression is eliminated, mice develop normally, but age to death by 4 months of age. This rapid deterioration is accompanied with a phenotype not unlike what is observed in aged humans (cognitive impairment, atherosclerosis, ectopic calcification, emphysema, osteoporosis, skin atrophy and hair loss, thymic involution, infertility and decreased bone mineral density). Elimination of Klotho in mice causes cognitive impairment that is associated with increased oxidative stress. In contrast, Klotho overexpressing transgenic mice live longer by up to 30% and are resistant to oxidative stress. Our group found that Klotho is downregulated in the aging non-human primate, rat and mouse brains Together, these have lead us to hypothesize that Klotho is important in brain function and its downregulation with age may be the result of oxidative stress which, if prevented, could ameliorate decline into neurodegenerative disease. The work proposed, examines regulation of the Klotho promoter and 3'UTR with age and the effect of oxidative damage to the Klotho promoter with age. We will determine whether the high GC content of the Klotho promoter makes it a target for age-related downregulation because of damage that accumulates over time because of oxidative stress. This will be done by comparing the oxidation state of the Klotho promoter to that of other genes both in vitro and in post mortem samples from aged rhesus monkey brain. We will also work to characterize the transcription factors that bind and induce activation of the Klotho promoter. The Klotho promoter does not contain the classical elements for transcription initiation. Understanding what factors are important for Klotho transcription may shed light on signaling pathways leading to Klotho activation and the role of Klotho in the normal cell. Last, we will determine whether Klotho is regulated by microRNAs (miR) and how miR change in the brain with age. MiR bind and regulate translation of mRNA and nothing is known about whether and how miR affect Klotho processing. Again, understanding the processes that regulate Klotho will enable us to have a better understanding of the processes that affect Klotho and Klotho's wider role in cellular function. The results of this work will add new knowledge on both the anti-aging gene Klotho and elucidate a possible mechanism for how oxidative damage selectively downregulates specific genes. PUBLIC HEALTH RELEVANCE: With a rapidly aging population, increases in age related disorders are anticipated to rise to unprecedented levels in the next 50 years. Understanding the regulation of genes known to effect and be affected by the aging process is critical to developing novel therapies for a range of disorders. The aging suppressor protein, Klotho is decreased in the brain with age and may be a target for therapeutic development against neurodegenerative disorders.